SACRAMENTO — California’s projected budget deficit has ballooned to $16 billion, much larger than predicted just four months ago, Gov. Jerry Brown said Saturday as he warned of draconian cuts to schools and public safety if voters don’t approve his November tax-hike measure.

The governor said the shortfall grew from $9.2 billion in January in part because tax collections are sluggish and the economy hasn’t recovered as quickly as expected. The deficit also has soared because lawsuits and federal requirements have blocked billions of dollars in state cuts to social programs, Brown said.

“This means we will have to go much farther and make cuts far greater than I asked for at the beginning of the year,” Brown said in an online video. “But we can’t fill this hole with cuts alone without doing severe damage to our schools. That’s why I’m bypassing the gridlock and asking you, the people of California, to approve a plan that avoids cuts to schools and public safety.”

Brown on Saturday did not release details of the newly calculated deficit through mid-2013, but he is set to lay out a revised spending plan Monday. The new blueprint for the fiscal year that starts July 1 hinges in large part on voters approving higher taxes in the fall. Under Brown’s tax measure, California would temporarily raise the state’s sales tax by a quarter-cent and increase the income tax on people who make $250,000 or more.

The bad news announced by Brown puts intense pressure on Democratic leaders, who in January had vowed to fight proposed cuts in Brown’s $92.5 billion budget because they believe they would rip apart an already fragile safety net.

“We will deal with it,” Senate President Pro Tem Darrell Steinberg said Saturday. “We know that more cuts are inevitable, but we will do our very, very best to save more than we lose, especially for those in need.”

Steinberg, D-Sacramento, said he wasn’t surprised by the deficit spike given that state tax revenues have fallen $3.5 billion below projections in the current year. He and other Democrats, who control the Legislature, have resisted Brown’s proposed cuts so far this year. And Republican lawmakers have criticized the majority party for building in overly optimistic tax revenues.

“Today’s news underscores how we must rein in spending and let our economy grow by leaving overburdened taxpayers alone,” Assembly Republican leader Connie Conway said in a statement.

Brown proposed $4.2 billion in cuts in January, including $1.4 billion to the state’s welfare-to-work program and state-subsidized child care.

Brown turned in 1.5 million signatures for his ballot measure Thursday, more than enough to put it before voters. If approved, the new taxes would generate about $7 billion annually.

Saving state parks

Democrats have already signaled they will reject Brown’s proposal to close 70 state parks July 1, promising to find the relatively paltry sum of $21 million in savings elsewhere in the budget to do so. And they are likely to resist major additional cuts to CalWORKs, the state’s welfare-to-work program, which has already withstood billions of dollars in reductions.

With a solid majority in both houses, Democrats can pass a budget easily, which has robbed Republicans of the power they once had to help shape the budget. But, as they found out last year when Brown vetoed their first budget, Democrats have to craft a plan that meets the governor’s approval.

Steinberg said Democrats won’t put themselves in a similar position this time because they share an interest in producing a balanced, on-time budget. The constitutional deadline for budgets is June 15, though legislators consider June 30, the end of the fiscal year, to be just as viable.

“We want to head into November having done our job together with the least amount of fuss and the least amount of fighting,” Steinberg said of the fall election.

But, he added, “there’ll be some.”

Problems in spotlight

Some political analysts believe Brown could benefit from a drawn-out budget fight.

“Advertising in October is important, but ongoing news coverage about what these cuts might entail is going to be more important to his campaign,” said Dan Schnur, director of the University of Southern California’s Jesse M. Unruh Institute of Politics.

Bickering over cuts “might be frustrating for Brown, but some heavy-duty Democratic push back against his budget is probably not such a bad thing,” Schnur said. “The louder they complain before they vote for it, the more they’ll raise awareness as to the potential impact.”

Critics have accused Brown of tailoring his budget to scare voters into supporting his measure. But Ace Smith, the campaign manager for the initiative, dismissed the charge.

“Voters already understand” how bad things have gotten, Smith said. “The worst mistake a campaign can make is to oversell something. There’s no need to oversell anything here because it’s plainly obvious.”

Advocates for the poor will hold protest rallies Monday across the state, including at the state building in San Jose, to coincide with the release of Brown’s revised budget.

Sandy Perry, an outreach minister for the homeless at the CHAM Deliverance Ministry in San Jose, said he was still outraged that Brown urged legislators to “man up” and make more cuts to welfare programs.

“How low can we sink as a country and as a people?” Perry said. “Yes, he’s trying to raise taxes slightly, but he’s still trying to put together these cuts. We hope we will be able to put enough pressure on the government to prevent these cuts.”

Steinberg said last week that he will draw the line on cuts to CalWORKs.

“I look at reports that show that cuts we’ve made in grant reductions and reduction in eligibility from five years to four have a direct correlation to increased homelessness,” Steinberg said. “I look at that and say we have to avoid that kind of cut at all cost. I’d do just about anything to avoid that cut. There is no powerful political constituency involved. This is just one of those ‘Can you sleep at night?’ kind of questions.”

In fear of cuts

One group with a powerful constituency, public employee unions, is in a vulnerable spot as well. After facing years of layoffs and furloughs, they now are bracing for more cuts. Their pay could be cut, or perhaps they’ll have to make higher contributions to pensions. The Brown administration would have to achieve savings through collective bargaining with a dozen units whose contracts expire in 2013.

Political analysts say Brown needs to send a strong message to voters.

“Brown has to make two sales,” said Bill Whalen, a fellow at Stanford University’s Hoover Institution. “One, he has to push voters’ buttons by offering 1,001 stories of human misery as a result of budget cuts.

“And two, he has to be willing to do something that will not please the public employee unions, show that they’re being hit, too. That would show he’s serious about these cuts.”

The Associated Press contributed to this report. Contact Steven Harmon at 916-441-2101. Follow him at Twitter.com/ssharmon.